Proper breathing is so important to keep your blood charged with vitality….Learn and practice this method: First, throw out the breath with a strong double exhalation (one short and one long breath). Then, inhale in a double inhalation (one short and one long breath), filling the lungs as full as is comfortable. Hold the air in the lungs for a few seconds, allowing the oxygen to be fully absorbed and converted into prana. Then repeat the double exhalation, followed by the double inhalation. Practice this method in the fresh air 30 times in the morning and 30 times at night. It is very simple. You will be healthier than ever if you follow this. This exercise brings in a great deal of extra life force; and also decarbonizes your blood, promoting calmness. - Paramahansa Yogananda.